compiler/rustc_target/src/lib.rs

   1 //! Some stuff used by rustc that doesn't have many dependencies
   2 //!
   3 //! Originally extracted from rustc::back, which was nominally the
   4 //! compiler 'backend', though LLVM is rustc's backend, so rustc_target
   5 //! is really just odds-and-ends relating to code gen and linking.
   6 //! This crate mostly exists to make rustc smaller, so we might put
   7 //! more 'stuff' here in the future. It does not have a dependency on
   8 //! LLVM.
   9
  10 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
  11 #![feature(assert_matches)]
  12 #![feature(associated_type_bounds)]
  13 #![feature(exhaustive_patterns)]
  14 #![feature(min_specialization)]
  15 #![feature(never_type)]
  16 #![feature(rustc_attrs)]
  17 #![feature(step_trait)]
  18 #![deny(rustc::untranslatable_diagnostic)]
  19 #![deny(rustc::diagnostic_outside_of_impl)]
  20
  21 use std::iter::FromIterator;
  22 use std::path::{Path, PathBuf};
  23
  24 #[macro_use]
  25 extern crate rustc_macros;
  26
  27 #[macro_use]
  28 extern crate tracing;
  29
  30 pub mod abi;
  31 pub mod asm;
  32 pub mod json;
  33 pub mod spec;
  34
  35 #[cfg(test)]
  36 mod tests;
  37
  38 pub use rustc_abi::HashStableContext;
  39
  40 /// The name of rustc's own place to organize libraries.
  41 ///
  42 /// Used to be `rustc`, now the default is `rustlib`.
  43 const RUST_LIB_DIR: &str = "rustlib";
  44
  45 /// Returns a `rustlib` path for this particular target, relative to the provided sysroot.
  46 ///
  47 /// For example: `target_sysroot_path("/usr", "x86_64-unknown-linux-gnu")` =>
  48 /// `"lib*/rustlib/x86_64-unknown-linux-gnu"`.
  49 pub fn target_rustlib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
  50     let libdir = find_libdir(sysroot);
  51     PathBuf::from_iter([
  52         Path::new(libdir.as_ref()),
  53         Path::new(RUST_LIB_DIR),
  54         Path::new(target_triple),
  55     ])
  56 }
  57
  58 /// The name of the directory rustc expects libraries to be located.
  59 fn find_libdir(sysroot: &Path) -> std::borrow::Cow<'static, str> {
  60     // FIXME: This is a quick hack to make the rustc binary able to locate
  61     // Rust libraries in Linux environments where libraries might be installed
  62     // to lib64/lib32. This would be more foolproof by basing the sysroot off
  63     // of the directory where `librustc_driver` is located, rather than
  64     // where the rustc binary is.
  65     // If --libdir is set during configuration to the value other than
  66     // "lib" (i.e., non-default), this value is used (see issue #16552).
  67
  68     #[cfg(target_pointer_width = "64")]
  69     const PRIMARY_LIB_DIR: &str = "lib64";
  70
  71     #[cfg(target_pointer_width = "32")]
  72     const PRIMARY_LIB_DIR: &str = "lib32";
  73
  74     const SECONDARY_LIB_DIR: &str = "lib";
  75
  76     match option_env!("CFG_LIBDIR_RELATIVE") {
  77         None | Some("lib") => {
  78             if sysroot.join(PRIMARY_LIB_DIR).join(RUST_LIB_DIR).exists() {
  79                 PRIMARY_LIB_DIR.into()
  80             } else {
  81                 SECONDARY_LIB_DIR.into()
  82             }
  83         }
  84         Some(libdir) => libdir.into(),
  85     }
  86 }